The invention pertains to preparation of m-phenoxybenzyl and m-phenoxybenzal halides. These products are useful as pesticide intermediates. In particular this invention relates to a process for reacting m-phenoxytoluene and a halogen at a temperature high enough to give, (i) a good yield of one or both of the aforementioned compounds, and (ii) an acceptable low amount of undesirable nuclear brominated by-product. The process is characterized further by being conducted without added phosphorus halide catalysis and without activation with ultra-violet radiation.
Thus, the process of this invention differs from the closest known prior art, viz U.S. Pat. No. 4,014,940, and U.S. Pat. No. 4,010,087. More particularly, U.S. Pat. No. 4,014,940, teaches the use of phosphorus halide catalysis and that appreciable aromatic halogenation can occur if such catalysis is not used. The other patent, U.S. Pat. No. 4,010,087, teaches u.v. irradiation of the reaction mixture.
In Examples I-IV of the patent which illustrate batch reactions, the yield of ring brominated by-product was 2-30%. With u.v. light and a continuous reaction, (Example V) almost no ring brominated material could be detected in the product.